Yarn traversing apparatus



Oct. 23, 1962 R. Y. HAYS YARN TRAVERSING APPARATUS Filed March 31, 1961FIGJ ID V +II 3,059,874 Patented Oct. 23, 1962 3,059,874 YARN TRAVERSINGAPPARATUS Richard Young Hays, Kinston, N.C., assignor to E. L du Pont deNemours and Company, Wilmington, Del., a corporation of Delaware FiledMar. 31, 1961, Ser. No. 99,833 6 Claims. (Cl. 242-1585) This inventionrelates generally to the traverse winding of yarn at high speeds andmore particularly to the reciprocating guides and followers employed ina yarn winding apparatus.

It is well known that substantially cylindrical packages of yarn, threador the like may be built on a bobbin in a traverse winding apparatuswherein the yarn passes through a reciprocating guide to a rotatingpackage. The guide is attached to a follower which rides in a generallyhelical groove in the surface of a rotatably driven barrel cam and isconstrained by one or more rails to a linear path of travel. Anapparatus of this type has been disclosed by Hunter in US. Patent No.2,689,694. Although such an apparatus is entirely suitable for use atthe speeds contemplated, it has been found that higher winding speedslead to the formation of unstable packages having bulged end faces andoverthrown ends. These difiiculties have been traced to the deposit ofsurplus yarn at the package ends as a result of the reduction infollower velocity in the reversal sections of the cam profile, i.e.,winding speed is frequently limited by the reversal time for the yarnguide. Theoretically the provision of a more angular reversal curvewould decrease the effect of this velocity reduction and facilitate anincrease in Winding speed. As a practical matter, the shoulders stillappear and, in addition, the nearly instantaneous change in directionsubjects the follower to excessive acceleration loads.

The general objective of the present invention is to improve theformation of packages wound at high speeds.

A further important object of the invention is to provide for anincrease in the speed of a yarn guide relative to its associated camfollower as the latter travels through the reversal sections of ahelical cam profile.

A corollary object is the provision of a cam follower and yarn guideassembly of such a construction that the reversal speed of the guide isincreased without any appreciable increase in the acceleration forcesacting on the assembly.

These and other objectives are accomplished by providing an assembly inwhich a yarn guide is attached to a cam follower in spaced relationshipto the turning center of the follower. During each reversal, the guidedeparts from its normal position relative to the cam profile, i.e., itswings outwardly and travels in a path which is both longer and moreangular than the reversal section of the cam profile.

Additional objects and advantages will become apparent in the followingspecification wherein reference is made by the use of designatingnumerals to the accompanying drawing in which:

FIGURE 1 is a plan view of a cam follower and yarn guide assembly madein accordance with the teachings of the present invention and shown inassociation with the cooperating parts of a yarn winding apparatus;

FIG. 2 is a fragmentary, sectional view taken on line II-II of FIG. 1;

FIG. 3 is a diagrammatic sketch of the reversal paths followed by thefollower and guide of FIGS. 1, 2;

FIG. 4 illustrates a plan view of a preferred embodiment of theassembly; and

FIG. 5 is a fragmentary sectional view taken on line V-V of FIG. 4.

The yarn winding apparatus chosen for illustration includes ascomponents thereof a rotatably driven barrel cam 10 having in itssurface a generally helical, continuous groove 12, a pair of guide rails14, 16 and a cam follower and yarn guide assembly 18. Assembly 18 isconstrained to a linear path of travel by rails 14, 16 and reciprocatingmotion is imparted thereto by the camming action of groove 12.

As shown in FIGS. 1 and 2, assembly 18 includes an elongated followerportion 20, a rail engaging portion 22, and a yarn guide 24. The latteris mounted at the extremity of one leg 25 of an L-shaped member 26, theother leg 27 of which is fixedly attached to follower 20 above itsturning center. Leg 27 also passes through and serves as a rotatablemounting for the rail engaging portion 22 which is also referred toherein as a slide element. Portion 22 has a groove in one side thereofwhich receives rail 16 and is in flat bearing engagement with rail 14 onits other side. As shown in FIG. 2, follower 20 is of an arcuateconfiguration which conforms generally to the surface contour of cam 10within groove 12.

In operation, assembly 18 is reciprocated by the camming action ofgroove 12 and in this manner yarn passing through the slot 23 in guide24 is traversed back and forth across a rotatably driven package (notshown) which is part of the traverse winding apparatus When the assembly18 is in a linear section of cam groove 12, each portion thereof followsa linear path of travel, i.e., there is no relative movement between thevarious portions of assembly 18. In the end or reversal sections ofgroove 12, follower 2t]- pivots about an axis which is substantiallyperpendicular to the rotational axis of cam 10. Leg 27 is also on thisaxis. As follower 2t pivots and thereby reverses its direction oftravel, its turning center follows the cam profile which has beendesignated with the numeral 36 in FIG. 3. Simultaneously, guide 24swings outwardly from profile 30- and follows a path 32. This path 32includes an additional increment of travel which is achieved by spacingguide 24 in leading or trailing relationship to the turning center offollower 20. Thus, a simple means for accelerating the yarn guide as itenters or leaves a reversal section has been provided. With thisimprovement, the speed of yarn windups may be increased withoutsubjecting the assembly to excessive acceleration loads since the guidereversal is accomplished in a time interval which is less than the timerequired for reversal of the follower 20. This reduction in guidereversal time reduces the shoulders which usually appear on the packageand thus leads to a more stable, uniform package outline.

The preferred embodiment of the assembly which has been illustrated inFIGS. 4 and 5 includes a follower portion 20', a rail engaging portion22, and a yarn guide 24'. Rail engaging portion 22 includes an integraldiamond shaped stud 48, the adjacent faces of which are alternately inengagement with one of the guide rails 14', 16'. It also includes anintegral pair of semi-circular plate elements 50, 52 which overlap andreceive rail 14 therebetween. The pivot axes of portions 20', 22' arecoincident. Guide 24 is attached to plate 50 and has a yarn receivingslot 23 which is spaced longitudinally from the turning center or pivotaxis of follower 20 and is also situated above the follower centerline.Thus, when the assembly 18 is in a linear section of the cam groove,slot 23' is above the groove centerline. As the assembly passes througha reversal, its turning center remains above the profile 3'0 but slot23' swings outwardly in a path 32 as shown in FIG. 3.

It is apparent that many changes and modifications may be made in thedisclosed cam follower and yarn guide assembly without departing fromthe spirit of the invention which is therefore intended to be limitedonly by the scope of the appended claims.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. In a yarn winding apparatus including a barrel cam provided with ahelical groove in its surface and at least one guide rail, a camfollower and yarn guide assembly comprising: an elongated follower insaid groove, said follower being adapted to pivot about an axissubstantially perpendicular to the rotational axis of the cam when inthe reversal sections of said groove; a yarn guide fixedly and immovablyattached to said follower for pivotal movement therewith about said axisand having a yarn-engaging portion in longitudinally spaced relationshipto said axis; and rail engaging means on said assembly for constrainingthe latter to a linear path of travel.

2. In a yarn winding apparatus including a rotatably driven barrel camprovided with a helical groove in its surface and spaced guide rails, acam follower and yarn guide assembly comprising: an elongated followerin said groove, said follower being adapted to pivot about an axissubstantially perpendicular to the rotational axis of the cam when inthe reversal sections of said groove; an integral stud projectingoutwardly from said follower along said axis, said stud being situatedbetween said rails and adapted to pivot about said axis with thefollower; an integral plate member extending from said stud toward oneend of the follower and in overlapping relationship to one of saidrails; and a yarn guide located on said plate member in spacedrelationship to said axis.

3. The apparatus of claim 2 wherein said stud is diamond shaped incross-section and has opposed parallel faces adapted for simultaneousengagement with said rails.

4. The apparatus of claim 3 wherein is provided a second integral platemember extending from said stud, both said plate members being inslidable engagement with said one rail.

5. In a yarn winding apparatus including spaced guide rails and arotatably driven barrel cam provided with a helical groove in itssurface, a cam follower and yarn guide assembly comprising: an elongatedfollower in said groove, said follower being adapted to pivot about anaxis substantially perpendicular to the rotational axis of the cam whenin reversal sections of said groove; an L-shaped member having a firstleg fixedly and immovably attached to said follower for pivotal movementtherewith about said axis and projecting outwardly on said axis and asecond leg extending toward one end of the follower in overlappingrelationship to one of said rails; a yarn guide located on said secondleg in spaced relationship to said axis; and a slide element situatedbetween said rails, said element being rotatably mounted on the firstleg of said member.

'6. The apparatus of claim 5 wherein said slide element is rectangularin cross-section and has a centrally disposed bore within which saidfirst leg is freely rotatable.

References Cited in the tile of this patent UNITED STATES PATENTS2,934,284 Steeger Apr. 26, 1960

